Electric terminal.



P. W. LYLE. ELECTRIC TERMINAL.

APPLICATION Hum 001'. 30, mu.

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STATES PATENT onnroa'.

LYLE, F LYNN, MASSACHUSETTS, ASSIGNOR T6 GENERAL ELECTBIG COMPANY, A CORPORATION OF NEW YORK.

' ELECTRIC TERMINAL.

Specification of Letters Patent.

f Application filed October 36, 1911. SerialNo. 657,516.

To all whom it may concern: 7 A I Be it known that I, FRED W. LYLE, a.citizen of the United States, residing atLyn'n, county of Essex, State of Massachusetts, have invented certain new and useful Improvements in Electric Terminals, of which the following is a specification.

My invention relates to electrical resistance or similar units consisting largely or "entirely of boron and has for its object the production of an effective current connece tion or terminal.

4 Electrical resistors consisting of elemental boron either alone or associated. with certain other elements, such as carbon, have .a very high negative temperature resistance coefficient which makes them very valuable. The quickness with which the resistor responds to changes of current increasesrapidly with the temperature atwhich it is operated. It is. desirable, therefore',to operate a resistor at high temperature when quick response is desired. In fact, even when not continually operating aboron. resistor at high temperature, it is desirable to have the temperature range of its operation as wide as possible.

I have found that the metals of the chromium group particularly tungsten and.

' struck with either of the welded materials fusing the cap or terminal to a boron re-- as this almost invariably produces overheating, and consequently cracking- I In the accompan g drawings, Figure 1 is an elevational view of an apparatus for sistor; Fig. 2 is an elevation taken at right angles to the view shown in Fig. 1 and Fig. 3 is a. sectional detailed view of the boron resistor with the terminal applied.

The process of joining the terminal to the rod of boron is preferably carried; out by heating the terminal and boron resistor while in contact by means of an arc struck between two independent. electrodes. This heating process is carried out in a reducing gas such as hydrogen, or in an inert atmos phere, in order to prevent the formation of oxids. Figs. -1 and 2 show the boron resistorl supported by long-handled. tongs 2 within a bell jar 3. The bell jar is supplied with hydrogen or other suitable gas'through a tube 4. As shown on the drawing, the tongs hold the boron rod in contact with the caps or terminals 5 by simple inechani: cal pressure; Carbon electrodes 6, 7 are held by 's-uitableelamps on tongs 8, one member of which 9' is adjustable both vertically and'horizontally by being) pivoted on the insulating block 10. This up and down the fixed rod which holds the elect-rode 6. Current is supplied by any suitable source of energy such as storage battery 11. An arc is'struck by contact between the electrodes 6 and 7 and then gradually approached to the outside of the .cap 5 which, as already mentioned, consists of tungsten, molybdenum or other metal of the same character. By; gradually bringing the rod and terminal :within, effective. heatradiating distance of the arc, the weld is look can bemoved efl'ected without cracking. The boron and i' the metallic cap are finally brought directly into the are, thus completing the .weld.

The high temperature causes the boron and the-metal of the terminal to chemically combine with the probable formation of an alloy whi-ch unites the rod and terminal into intimate conducting relation.

I have found tantalum to alloy with boron and to make a fairly good terminal, but the resulting alloy is somewhat brittle. I consider tungsten to be the most suitable metal for the purpose of my invention.

' As shown in Fig. 3, I prefer to extendthe metal cap 5 some distance outwardly from the end of the boron rod 1 to secure a certain amount of cooling effect at this region,

' and thus to enable su1table current connectionsto be made with. convenience. v

What I claim as new and desire to secur by Letters Patent of the UnitedStates, is,-

1. An electrical resistance consisting largely of elemental boron having a terminal consisting of a metal of the chromium group in intimate conducting relation thereto.

2. Anelectrical resistance composed.

largely of boron and having a tungsten rial'and' boron integrally joining the termi- 1 terminal welded thereto.

3. An electrical resistance composed of largely of boron, a terminal welded thereto consisting of a refractory material and an intermediate refractory alloy of. said matenal to the boron.

In witness whereof, I havehereunto set my'hand' this 26th day of October 1911.

FRED W. LYLE Witnesses:

v JOHN A. LICMANUS, Jr., FRANK Gr. HA'rrm. 

